Electric contact member and production method thereof

Abstract

An electric contact member has a texture wherein fire proof metal powder having the form of a flat plate is diffused in a matrix of a highly conductive metal. The flat surface is oriented in one direction and the surface in parallel with the flat surface of the fire proof metal powder is used as a contact point face.

What is claimed is:  
     
       1. A vacuum valve, comprising: 
       a vacuum container; and  
       first and second electrodes provided on fixed and movable sides, respectively, in the vacuum container;  
       wherein each of said first and second electrodes includes an electric contact member produced by dispersing fireproof flat metal powder particles into a matrix comprising a highly conductive metal, followed by pressure molding the matrix and then sintering the pressure-molded matrix;  
       wherein the electric contact member comprises a sintered body that is sintered after pressure molding; and  
       wherein the flat surfaces of said fireproof flat metal powder particles are oriented in one direction, and said electric contact member has a contact point face surface that is parallel to the flat surface of said fireproof flat metal powder particles.  
     
     
       2. A vacuum valve according to  claim 1 , further comprising: 
       first and second electrode rods connected to the first and second electrodes, respectively;  
       wherein said vacuum container is cylindrical; and  
       a value y obtained by multiplying the rated voltage (kV) by breaking current effective value (kA) is not more than the value obtained by the following equation (1) and not less than the value obtained by the following equation (2), based on the outer diameter x (mm) of said vacuum container:  
       
         
             y= 11.25 x− 525  (1)  
         
       
       
         
             y= 5.35 x− 242  (2).  
         
       
     
     
       3. A vacuum valve according to  claim 1 , further comprising: 
       first and second electrode rods connected to the first and second electrodes, respectively;  
       wherein the diameter y (mm) of each said electric contact is not more than the value obtained by the following equation (3) and not less than the value obtained by the following equation (4), based on the value x (kVA×10 3 ) obtained by multiplying the rated voltage (kV) by breaking current effective value (kA):  
       
         
             y= 0.15 x+ 22  (3)  
         
       
       
         
             y= 0.077 x+ 20  (4).  
         
       
     
     
       4. A vacuum valve according to  claim 1 , further comprising: 
       first and second electrode rods connected to the first and second electrodes, respectively;  
       wherein said vacuum container is cylindrical; and  
       the outer diameter y (mm) of said vacuum container is within the range from the value obtained by the following equation (5) or less to the value obtained by the following equation (6) or more, based on the diameter x (mm) of said electric contact:  
       
         
             y= 1.26 x+ 30  (5)  
         
       
       
         
             y= 1.26 x+ 10  (6).  
         
       
     
     
       5. A vacuum valve according to  claim 1 , wherein said fireproof flat metal powder particles each have a characteristic in which maximum flat surface length of said particles divided by minimum dimension of a surface perpendicular thereto of said particles is within the range from 3 to 30. 
     
     
       6. A vacuum valve according to  claim 1 , wherein 90 wt % or more of the fireproof flat metal powder particles have a flat surface oriented with respect to the contact point face within the range from +40 to −40 degrees. 
     
     
       7. A vacuum valve according to  claim 1 , wherein 75 wt % or more of the fireproof flat metal powder particles have a flat surface oriented with respect to the contact point face within the range from +20 to −20 degrees. 
     
     
       8. A vacuum valve according to  claim 1 , wherein the fireproof flat metal powder particles comprise one of Cr, W, Mo, Ta, Nb, Be, Hf, Ir, Pt, Zr, Ti, Te, Si, Rh and Ru, a mixture comprising two or more of them, or a compound thereof; and the highly conductive metal comprises Cu, Ag, Au or an alloy mainly consisting of them. 
     
     
       9. A vacuum valve according to  claim 1 , wherein the fireproof flat metal powder particles contain 50 to 2000 ppm of oxygen, 50 to 3000 ppm of aluminum and 100 to 2500 ppm of silicon. 
     
     
       10. A vacuum valve according to  claim 1 , wherein the vacuum valve is 15 to 40 wt % of the fireproof flat metal powder particles, and 60 to 85 wt % of the highly conductive metal. 
     
     
       11. A vacuum valve according to  claim 1 , wherein the percentage of the area of the contact point face which is occupied by the fireproof flat metal powder particles is 30 to 50%, and the percentage of the area of the surface perpendicular to the contact point face which is occupied by the fireproof flat metal powder particles is 14 to 25%. 
     
     
       12. A vacuum valve according to  claim 1 , wherein the fireproof flat metal powder particles contain 2500 ppm or less of oxygen. 
     
     
       13. A vacuum valve according to  claim 1 , wherein tensile strength of said electric contact member in the direction perpendicular to the contact point face is 150 MPa or less. 
     
     
       14. A vacuum valve according to  claim 1 , wherein the specific resistance of said electric contact member is 5.5 μΩ.cm or less.